Along with "Hike Your Own Hike," it's equally important to "Pick Your Own Pitch" and "Choose Your Own Tarp." Just as there are as many hammock options to choose from, there are equally as many tarp configurations and rigging options to match.
When it comes to tarps, some like full coverage while others prefer to go topless. There's no right or wrong answer here, and your choice depends on many factors: weight, coverage, versatility, ease-of-use, etc.
It is generally agreed that full-coverage tarps, or "winter" tarps are best for four-season camping when you need maximum protection from the elements. Winter tarps usually add extra flaps or "doors" to the ends of the tarp that can be folded inward to enclose all four sides. Some manufacturers sell "doors" as an optional add-on to common hex or cat-cut tarps.
Large tarps also provide good privacy for modesty when changing clothes, etc. But larger tarps can be more complicated to pitch for some users and they do weigh more and can require extra hardware (e.g., stakes, guylines) to pitch.
In moderate conditions, almost any tarp can be modified for good coverage, ventilation, and privacy. Some users have successfully used ponchos as dual-purpose a-sym tarps. Diamond tarps offer more coverage than a-sym design and are equally simple to pitch. Keep in mind, however, that smaller tarps require greater skill to keep dry in adverse conditions. It is often necessary to sleep in a specific direction under an a-sym tarp to maximize coverage.
Square or rectangular tarps with multiple tie-outs can allow for greater pitching options than other tarps.
One great advantage of hammock camping with tarps is that in adverse conditions--rain, snow, wind--you can set up the tarp first and then keep your gear dry as you set up the hammock and sleep system. The first part to hanging the tarp is the ridgeline. As with tarps, there are multiple methods: end tie-outs or full ridgelines; knots, prusik loops, figure-9, knot bones, etc. The amount of versatility means each hanger can pick what works best for them, balancing weight, strength, ease-of-use, or other metrics.
Most ridgelines fall under one of two categories: end-only or full-length. End-only lines essentially eliminate the rope between the tarp tie-outs, which can reduce some weight. Full-length ridgelines run the entire length of the tarp and can be used under the tarp or over the tarp.
With a full-length ridgeline, you can set the line first and then adjust the tarp along the line to center it. It is often easier to center a tarp between the supports with a full-length ridgeline than with end-only lines.
Hanging the tarp over a full-length ridgeline provides additional structure and can be preferred during extreme conditions when the ridgeline can help support extra weight, such as during a snow storm. With the ridgeline running under the hammock, it also provides handy points for clipping gear to air dry, or to attach a bug net.
Whether you use a full or end-only ridgeline, one method for attaching the line to the support is to create a "V" around the post (see illustration). Essentially, you begin to loop the line around the support starting at the end point of the tarp. You then take the line around the support and then attach the line back at the beak of tarp. This creates a space so the hammock suspension can swing with less collisions against the tarp suspension line.
Once the ridge of the tarp is set, you can set the guylines. Diamond or asymmetric tarps have as little as two guy points, so set-up can be quicker. Guylines of approximately 6 feet allow enough line so you can guy the tarp around other nearby supports, pitched low during adverse conditions, or in conjunction with trekking poles or found supports to open the tarp for more ventilation or views.
Many tarps stretch during the night, so even the tightest pitch before going to bed may slacken by morning. You can retrofit guylines with elastic shock cord or purchase them ready-made from several manufacturers. With shock cord on the guyline, the tarp will remain taut as the tarp stretches.
I hope these two illustrations provide some basic understanding for the more common types of tarps used with hammocks and some best practices for pitching and using hammock tarps.